The 1968 Ferrari 275 GTS/4 NART Spider was one if just 10 assembled and it was the only one sold originally in Europe.
This Spider is an ultra rare Ferrari and is due to be sold at the upcoming Monaco Historic Grand Prix and could sell for upwards of $26 million.
1968 Ferrari 275 GTS /4 NART Spider
http://www.motorauthority.com/news/1103544_rare-ferrari-could-fetch-up-to-26-million-at-auction